Human exposure to particulate pollutants having a size below 10 μm, particularly those below 0.1 μm, has been strongly associated with adverse health effects due to their ability to be inhaled deeply into the respiratory system. A large number of particle collectors are commercially available for monitoring ambient air quality, worker health and safety, process manufacturing, and so forth. The U.S. Environmental Protection Agency has established an extensive network of samplers that routinely collect ambient particles for monitoring air quality and compliance to the National Ambient Air Quality Standards.
Particle collectors based on electromagnets have been used, but a significant drawback is the requirement of a power source. Although particle collectors based on permanent magnets are also known, they generally exhibit less than desirable collection efficiencies for particles having very small particle sizes of less than 100 nm, which are often the most important types of particles to collect in view of their particularly adverse health effects.